I'm looking at yurt and build-with function doesn't seem to exist. Where is it?

Hmmm, looks like this function was removed in favor of some other way. Documentation in README needs updating.

@pauld good catch, thanks. build-with and build-only were deprecated in favor of :swap and :only options. docs are updated: https://github.com/tolitius/yurt#swapping-alternate-implementations

cool thanks - yeah I figured that's what happened - cheers!

I still see three more references to build-with in the readme

yea, they are gone now, I noticed them after updated the sections